Apparatus and method for clay baking



Nov. 27, 1951 p, E, KOPP APPARATUS AND METHOD FOR CLAY BAKING Filed Jan. 11, 1949 2 SHEETS- SHEET l Nov. 27, 1951 P. E. KOPP APPARATUS AND METHOD FOR CLAY BAKING 2 SHEETS-SHEET 2 Filed Jan. ll, 1949 INVENTOR @/7/7//5 E /VO/O/O BY /97' /P/VEK Patented Nov. 27, 1951 APPARATUS AND METHOD FOR CLAY BAKING Philip E. Kopp, Youngstown, Ohio Application January 11, 1949, Serial No. 70,261

This invention relates to clay baking and more particularly to the drying and baking of clay products such as nue tile and the like.

The principal object of the invention is the provision of apparatus and the method for baking clay products.

A further object of the invention is the provision of apparatus for the continuous production of baked clay products.

A still further object of the invention is the provision of a method of producing baked clay products on a continuous production line.

A still further object of vthe invention is the provision of an apparatus incorporating dielectric heating of the non-conducting clay materials processed.

A still further object of the invention is the provision of a method of using dielectric heating in the drying and baking of clay products.

The apparatus and method relating to the baking of clay products as disclosed herein contemplates the elimination of the heretofore believed necessary forming, air drying and kiln baking of clay products and the heretofore necessary relatively long time interval for accomplishing these several successful operations. The invention may be practiced in the formation of any clay product or any other product formed of non-conducting material wherein the removal of moisture from the product in pre-baking stages is essential and the controlled heating and cooling of the object is necessary to the end that a product be produced that is not warped, cracked or otherwise rendered unsatisfactory for use.

It is known that dielectric heating has the ability to create heat within non-conducting materials uniformly throughout the material and the apparatus and method disclosed herein utilize such dielectric heating by subjecting the clay product to a suitably controlled high frequency i'leld existing between two metallic surfaces having a relatively high difference of potential therebetween. As the dielectric heating creates heat instantly Within the materials rather than forcing the heat from the outside surface, it is particularly adaptable for the drying and baking 'of clay products wherein a considerable moisture `content exists in the initial stages of processing.

With the foregoing and other objects in View which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise 3 Claims. (Cl. 219-47) vtrodes I8.

embodiment of the invention herein disclosed can be made within the scope of what is claimed without departing from the spirit of the invention.

The invention is illustrated in the accompanying drawing, wherein:

Figure 1 is a side View with parts broken away and parts in cross section illustrating apparatus for drying and baking clay products.

Figure 2 is a horizontal section taken on line 2 2 of Figure 1.

Figure 3 is a vertical section taken on line 3 3 of Figure 1. n

Figure 4 is an enlarged detail view of a portion of the vapparatus shown in Figure l.

Figure 5 is a schematic view of a source of radio frequency currents for the apparatus shown in Figures l through 4.

By referring to the drawings and Figures 1 and 2 in particular it will be seen that a conveyor I0 is positioned for the reception of clay products such as iiue tile and indicated by the letter C and energized as by a motor and gear reduction box II. The clay products C are carried from right to left of the apparatus as illustrated in Figures 1 and 2 of the drawings and it will be observed that a plurality of infrared drying lamps I2 or their equivalent surround the clay products C on the conveyor I0 as they are moved thereby. In order that the clay products C may be uniformly heated, the conveyor II is preferably formed of chains having a plurality of relatively thin rods spacing the same so that the infrared lamps I2 or their equivalent beneath the conveyor I0 may radiate heat on all surfaces of the clay products C. Positioned in end to end relation to the conveyor I0 there is a roller table I3 having a plurality of rollers I4 positioned transversely thereof and spaced with respect to one another so that they may receive and support a clay product C delivered thereto by the conveyor I0. Each of the ends of the rollers I4 is provided with sprockets I5 and a continuous chain I6 is passed thereover and is also engaged upon a driving sprocket II powered by the motor and gear reduction box I I heretofore referred to.

A plurality of electrodes I 8 are positioned above the roller table I3 and in spaced relation to one another and a plurality of ground potential electrodes I9 are positioned in the surface of the roller table I3 and immediately below the path of the clay products C moving therealong. The electrodes I9 are aligned vertically with the elec- Positioned alternately between the spaced electrodes I8 and I9 there are electrodes 20 and 2I which are positioned on a vertical line and disposed along the sides of the path of the clay products C. The electrodes 20 on the other side of the apparatus are connected along with the electrodes I8 to a suitable source of radio frequency currents and the electrodes 2I are maintained at different potential along with the electrodes I9 heretofore referred to. The clay products moving along the rollers I4 of the roller table I3 are therefore subjected alternately to dielectric heating currents on vertical and horizontal planes, respectively, to the end that controlled baking of the clay products C may be accomplished.

It is known that the degree of heat generated in an object by the molecular movement therein varies in accordance with the frequency of the current passed therethrough. Thus, the'higher the frequency of current passed through the article, the higher the heat created as the high frequency current creates a .disturbance of the molecules of the material in the dielectric heat.- ing field. It is therefore desirable to control the heating of the clay products and particularly the baking stage thereof by bringing up the temperature of the clay product on a predetermined cycle so that warping and cracking of the article will not occur` To this end the electrodes i8 and 20 are grouped in several groups as best illustrated in Figures 4 and 5 .of the drawings and those electrodes adjacent the conveyor Iii and which the -initial baking heat to the clay products C are energized at a lower frequency than lthose further along the roller table I3 so that the heat of the clay products may be built up progressively as the same pass along the roller table I3 .and into and through the baking zone.

By referring now to Figures 4 and 5 of the drawings it will be seen that a circuit Wire 22 connects one group of the electrodes is with the .v

dielectric current source while another circuit wire 23 connects a different group of the electrodes I8 with another current source of a higher frequency. The power source shown in Figure of the drawings in schematic view comprises an alternating current power supply generally indicated by the numeral 24 incorporating breakers 25 and a high voltage direct lcurrent rectifier and transformer 26. The output vof the rectifier and transformer 26 is .supplied to oscillating tubes 27 and connecting circuits 23 which in turn are connected directly or indirectly to the circuit wires 22 and 23 heretofore mentioned in connection with Figure 4 of the drawings. Separate power sources are utilized for the different radio frequencies I necessary as heretofore described or the incorporation of a frequency changer 29 in one of the circuit vwires 22 or 23. It will thus be seen that `clay products C passing along the roller table I3 by reason of the powered rollers I4 will be subjected to dielectricV heating currents on both vertical and horizontal planes and at higher frequencies as they progress through the .apparatus whereby a satisfactory baking operation may be obtained.

Upon leaving the area of the electrodes I8, le, 20 and 2I, the clay products C continue to roll along in an extended section I3A of the roller table I3 .and including transversely positioned powered rollers I4 and into a control cooling chamber 30. Cooling air is introduced into the cooling chamber 30 by a blower `3| and the air passes progressively over the clay products C and is then directed by .a duct 32 around the dielectric vbaking section .of the apparatus V:and 'into a chamber 33 in which the infrared, preheating lamps I2 or their equivalent are positioned. The heated air is directed by suitable baffles 34 onto the clay products C entering the apparatus on the conveyor I D and with the preheated air materially assists in the drying operation necessary as a preliminary step to the baking operation heretofore described. It will be obvious that if desired the infrared heating units I2 may be `de-energized during the continuous operation of the device as suicient preheated air is delivered to the chamber 33 to efficiently dry the clay products C.

In operation the apparatus is aligned end to end with the press producing the clay products so that the product of the press may be produced directly onto the conveyor I0 from whence the clay product is dried yand delivered to the roller table I4 and passed to the dielectric heating stage for baking. It is then cooled at a desirable rate by the air cooling currents in the chamber 30 and delivered from the far end of the apparatus in completed form.

It will thus be seen that the hand operations heretofore believed necessary in the production of clay products are eliminated by the provision of apparatus and method for continuously producing the -clay products and which clay products may be operated intermittently, if desired, without affecting the quality of the clay products produced therein, It will also be seen that the apparatus and method disclosed herein meet the several other objects of the invention as hereinbefore set forth to `the end that an efcient clay drying, baking Vand cooling procedure has been disclosed. utilizing controlled .dielectric heating for baking of the clay products.

Having thus -described my invention, what I claim is:

1. The method of baking clay products wherein the clay products .are moved horizontally and dried, and subsequently subjected to .dielectric heating Vcurrents of one frequency and subsequently subjecting the clay products to dielectric heating currents of a higher frequency, and subsequently cooling the clay products by subjecting the same to a cooling medium whereby the clay products may be predried, progressively baked and cooled.

2. The method of baking clay products wherein the clay products are dried and subsequently moved so as to subject the clay products alternately to dielectric .currents directed vertically therethrough and dielectric currents directed horizontally therethrough and lof progressively higher frequencies for progressively baking the said clay products uniformly and subsequently subjecting the clay products to a cooling medium for controlling the cooling rate thereof.

3. .Apparatus for continuously producing baked clay products and including longitudinally extending conveying means, a chamber positioned about one lend of the said conveying means adjacent the point Aof introduction of the said clay products, a plurality of oppositely disposed pairs of .electrodes positioned alternately above, below and at the sides of the said conveyor, a source of dielectric heating currents and means connecting :the said electrodes adjacent the said chamber with the said -source of dielectric currents, a secondary source of higher frequency dielectric heating currents and means connecting the others of the velectrodes with the said secondary source of dielectric heating current., and a second- :ary chamber .formed about the said conveyor and .at the opposite. end thereof with respect to the rst mentioned chamber, and means for introducing air thereinto and duct means by passing the said electrodes and connecting the said chambers to one another whereby air heated in cooling the baked clay products is directed through the duct `and into the rst mentioned chamber and used for drying the clay products when the apparatus is in continuous operation.

PHILIP E. KOPP.

REFERENCES CITED UNITED STATES PATENTS Name Date Harper et al June 22, 1909 Number Number Number 15 566,927 605,806

Name Date Jeffery Sept. 25, 1923 Stephen Feb. 11, 1941 Wilson May 11, 1943 Grell et al Jan. 28, 1947 Kline et a1 May 27, 1947 Rowe Feb. 24, 1948 Beaubien Nov. 23, 1948 Klingel-man Mar. 15, 1949 Gillespie Mar. 15, '1949 Jones June 7, 1949 FOREIGN PATENTS Country Date Great Britain Jan. 19, 1945 Great Britain July 30, 1948 

